JPH0477705A - Manufacture of optical waveguide - Google Patents

Abstract

PURPOSE:To obtain an optical waveguide not to generate a waveguide loss even in the case of using it at a certain place in a normal environmental condition excepting for a clean room by covering four peripheries around an optical waveguide part with a crack material. CONSTITUTION:A clad base material composed of the resin of a low refraction factor forming a recessed groove 2 for which a high refraction factor resin is charged, to be the optical waveguide part is completely covered with a clad member 5 composed of a low refraction factor material. A core member 3 is charged into a void formed by the clad member 5 in the recessed groove 2 by utilizing a capillary phenomenon or injecting resin. The core member 3 is composed of the transparent plastic resin of the high refraction factor and uses a synthetic resin such as polystyrene or polycarbonate, etc. Since the four peripheries of the core member 3 are completely covered with the crack member for an optical waveguide 20 having this structure, a foreign material such as dust is not stuck onto the core part 3 and the core part is not damaged.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing an optical waveguide, and more specifically, a method for manufacturing a polymer optical waveguide used in optical systems such as communication and information equipment. It is related to.

[Prior Art] Conventionally, a substrate is produced by pouring a transparent plastic resin with a low refractive index into a mold, and then a part of the mold is removed, and a thin strip-shaped cavity is formed on the substrate instead. There was a method of forming a waveguide bonded to the substrate by stacking molds such as these and pouring a plastic resin with a high refractive index into the cavity (Japanese Patent Laid-Open No. 12,000/1989).
(See Publication No. 4, hereinafter referred to as Prior Art 1).

In addition, transparent casting resin is flowed in from one end of the pattern groove of a flat silicone rubber mold with a waveguide pattern formed in the shape of a concave groove using capillary action, and the resin is sufficiently filled into the groove. After that, let it harden. Next, a casting resin having a lower refractive index than the resin filled in the groove is poured over the entire surface on which the pattern is formed and hardened. After that, the molded product in which the patterned resin and the flat resin cured product are integrated is removed from the silicone rubber mold, and a low refractive index resin is again applied to the entire surface of the molded product on the side where the waveguide pattern is formed. There is a method of manufacturing optical waveguides by casting and curing (
See Japanese Patent Application Laid-Open No. 61-138903, hereinafter referred to as Prior Art 2
).

[Problems to be Solved by the Invention] However, in the optical waveguide obtained by the molding method of Prior Art 1, the upper surface of the core material that becomes the optical waveguide portion is not covered with the cladding material, so dust etc. If foreign matter adheres to the material or the material is scratched, the light will be scattered and the waveguide loss will become extremely large.Also, the effective reflection surface of the light is % wavelength smaller than any interface between the core material and the clad material. Since the core is on the cladding material side, even if there is dust floating in the air layer above the core that is not covered by the cladding material, light will be scattered, which will have a negative effect on the waveguide loss as described above. In order to prevent deterioration of waveguide loss caused by dust and scratches, it was essential to package the entire optical waveguide.

Although Prior Art 2 satisfies the above requirements, not only is the process for forming the guiding waveguide complicated and time-consuming, but also the casting and curing of low refractive index resin is difficult. It takes a long time to prepare, and is inefficient and unsatisfactory as an industrial manufacturing method.

The present invention was made to solve the above-mentioned problems, and there is no need to package the entire optical transmission circuit, and the waveguide loss worsens when used not only in a clean room but also in a normal location. An object of the present invention is to provide a method for manufacturing an optical waveguide, which eliminates the risk of foreign matter such as dust adhering to the core part or causing damage to the core part, and which allows the formation of a guiding waveguide easily and in a relatively short time. That is.

[Means for Solving the Problems] The present inventor has devised a simple method for creating an optical waveguide in which a waveguide portion made of a high refractive index material that causes no problem in terms of waveguide loss is completely covered with a cladding material made of a low refractive index material. As a result of careful consideration of manufacturing methods in a short time using simple operations, we developed a method that uses a mold to form a clad base material with grooves in which the desired waveguide pattern is formed and a clad covering material that covers the optical waveguide section. The cavity formed by overlapping the clad base material and the clad covering material is filled with a high refractive index resin and cured to form an optical waveguide in which the waveguide portion is completely covered and protected. They found that it can be formed easily and in a short time, and have completed the present invention. That is, the present invention provides a method for manufacturing an optical waveguide formed using plastic materials having different refractive indexes, in which a clad base material having a waveguide pattern formed in the shape of a concave groove and a clad covering material are formed into a thin strip-shaped cavity. and filling this cavity with a plastic material having a higher refractive index than the plastic material forming both of the cladding materials to form an optical waveguide integrally joined with both of the cladding materials. The gist of the present invention is a method for manufacturing an optical waveguide characterized by the following.

The present invention will be explained in detail below with reference to the drawings. FIG. 3 is a perspective view of an optical waveguide fabricated using the method according to the present invention, in which 1 indicates a groove 2 filled with a high refractive index resin which becomes a leading waveguide section.
This is a clad base material made of a low refractive index resin. This base material is a plastic product pre-molded by injection molding, casting, compression molding, or any other suitable molding method using, for example, transparent polymethyl methacrylate, methyl pentene polymer, or the like.

Note that a recess 7 is provided on the joint surface 4 of the clad base material 1 with the clad covering material 5 at a position corresponding to the protrusion 9 provided on the joint surface 6 of the clad covering material 5 with the clad base material 1. The clad base material 1 and the clad covering material 5 can be easily aligned, and the two can be superimposed even more easily.

The cladding material 5 is a plastic product pre-molded using a low refractive index resin, similar to the cladding base material 1.
From the viewpoint of ease of joining, it is preferable that both are plastic products made of the same resin. The core material 3 is made of a transparent plastic resin with a high refractive index, and for example, a synthetic resin such as polystyrene or polycarbonate is used. In an optical waveguide with such a structure, the four circumferences of the core material 3 are completely covered with the cladding material, so that there is no possibility of foreign matter such as dust adhering to the core part or damage to the core part, so there is no waveguide loss. will no longer be adversely affected. Next, a method for manufacturing an optical waveguide having the structure shown in Fig. 3 will be explained in Figs.
This will be explained using figures. FIG. 1 is a perspective view of the clad base material, and the groove 2 is formed as described above on the joint surface 4 of the clad base material 1 with the clad covering material 5, and a recess 7 is further provided as necessary. It will be done. FIG. 2 is a perspective view of the cladding material 5, in which a protrusion 9 is formed on the joint surface 6 formed on a plane that contacts the joint surface 4 of the clad base material 1.
If a recess 7 is formed in the joint surface 4 of the recess 7, the protrusion 9 is formed at a position corresponding to the recess 7, and the protrusion 9 is dimensioned to easily fit into the recess 7. ing. In this way, the protrusion 9 is fitted into the recess 7 using the jig 11 as shown in FIG. 4 so that the rad base material 1 and the clad covering material 5 are overlapped as shown in FIG. and the peripheries of the joint surfaces 4 and 6 are arranged so as to be adjacent to the inductor 15 connected to the high frequency induction heating device 13, and high frequency is oscillated to instantaneously heat both the joint surfaces.
The clad base material 1 and the clad covering material 5 are melted and adhered to each other. Incidentally, FIG. 4 is a schematic diagram after the two have been melted and brought into close contact with each other. At this time, the protrusion 9 serves to reliably seal the adjacent core materials 3 and the clad base material 1 and the clad covering material 5.
It also has the effect of facilitating melting and adhesion. Therefore, by attaching a substance that absorbs high frequencies well, such as ferrite or SiC, to the surface of part or all of the protrusion 9, or by incorporating it into the protrusion 9,
The clad base material 1 and the clad covering material 5 can be bonded more effectively. Thereafter, the cavity formed by the groove 2 and the joint surface 6 is filled with the core material 3 using capillary action or by resin injection.

In this case, injection molding of the core material 3 may be started by inserting the melted and tightly bonded cladding material into the mold, creating a vacuum inside the mold, and controlling the mold temperature, time, and injection pressure. moreover,
Using an inductor sandwiching type or built-in type mold as disclosed in Japanese Patent Application Laid-Open No. 57-4748, the clad base material l and the clad covering material 5 are melted and bonded by high frequency heating, and then If the core material 3 is filled in the same mold, the manufacturing time of the optical waveguide 20 can be further shortened.

Alternatively, the above procedure may be changed to first mold the clad base material 1 and the clad covering material 5, and then mold the clad base material l.
The core material 3 is formed by injecting and filling the high refractive index resin for forming the core material 3 into the concave groove 2 by capillary action, or by filling it by resin injection following the molding of the clad base material 1. Thereafter, the protrusion 9 of the cladding material 5 is fitted into the recess 7 using the jig 11, and then the cladding base material 1 and the cladding material 5 are melted and adhered by heating with high frequency in the same manner as above. Optical waveguides can also be manufactured.

[Example] Hereinafter, an example embodying the present invention will be described with reference to the drawings.

First, a clad base material 1 having grooves 2 and recesses 7 as shown in FIG. 1 was formed by injection molding a low refractive index resin (for example, polymethyl methacrylate resin) having a refractive index of about 1.5.

Next, as shown in FIG. 2, a cladding material having projections 9 at positions corresponding to the recesses 7 was injection molded using the same resin as above. The size of the protrusion 9 is the same as that of the recess 7.
The ferrite powder is thinly coated on its entire surface.

The clad base material 1 and the clad covering material 5 thus formed are faced to each other so that the protrusion 9 fits into the recess 7, and are engaged using a jig 11 as shown in FIG. The inductor 15 of an inductor sandwiching type mold (the mold is not shown) provided on the inner surface of the inductor 11 is installed so that the peripheries of the bonding surfaces 4 and 6 are adjacent to each other, and high frequency waves are oscillated for 10 seconds from the high frequency induction heating device 13. Then, the bonding surfaces are instantaneously heated, the clad base material 1 and the clad covering material 5 are melted and brought into close contact with each other, and the adjacent grooves 2 are reliably sealed to form a band-shaped cavity. Next, a high refractive resin (for example, polystyrene resin) with a refractive index of about 1.6 is injected into the cavity for 5 seconds while the inside of the mold is evacuated to form the core material 3, and then cooled for 10 seconds and then molded. It was taken out from the mold to obtain an optical waveguide 20 shown in FIG.

Total cycle time was 35 seconds.

[Effects of the Invention] As detailed above, according to the present invention, the four circumferences of the optical waveguide section are completely surrounded by the cladding material.
Optical waveguides that do not require packaging of the entire transmission path and are not affected by waveguide loss even when used in locations other than clean rooms under normal environmental conditions can be manufactured easily and in a short time, making it possible to manufacture them in large quantities. Moreover, there is an advantage that the optical waveguide can be manufactured at low cost.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of the cladding base material of the present invention, FIG. 2 is a perspective view of the cladding material of the present invention, FIG. 3 is a perspective view of an optical waveguide manufactured by the manufacturing method of the present invention, and FIG. 4 is a perspective view of the cladding material of the present invention. FIG. 2 is a schematic diagram of an apparatus for joining a clad base material and a clad covering material by high-frequency induction heating, and a clad material after melting and adhesion. DESCRIPTION OF SYMBOLS 1... Clad base material, 2... Concave groove, 3... Core material, 4... Joint surface, 5... Clad covering material, 6...
Joint surface, 7 recess, 9... protrusion, 11... jig, 1
3... High frequency induction heating device, 15... Inductor, 20... Optical waveguide.

Claims (5)

[Claims] (1) In a method for manufacturing an optical waveguide formed using plastic materials with different refractive indexes, a thin band-shaped cavity is formed between a clad base material having a waveguide pattern formed in the shape of a groove and a clad covering material. and the cavity is filled with a plastic material having a higher refractive index than the plastic materials forming both of the cladding materials, thereby forming an optical waveguide integrally joined with both of the cladding materials. A method for manufacturing an optical waveguide. (2) The method for manufacturing an optical waveguide according to claim 1, wherein the bonding surface of either the clad base material or the clad coating material is a surface having a protrusion. (3) Claim 1, wherein the method of joining the clad base material and the clad covering material is a high frequency heating method.
A method of manufacturing the optical waveguide described above. (4) The method for manufacturing a photoconductive path according to claim 1, wherein the method for filling the core material into the cavity is an injection molding method or a method using capillary phenomenon. (5) Claim 1 characterized in that the joint surface of either the clad base material or the clad covering material is a surface having a protrusion containing or adhering to a high-frequency high-absorbing material.
A method of manufacturing the optical waveguide described above.